Abnormal cells in the body are known to selectively absorb certain dyes that have been perfused into a treatment site to a much greater extent than absorbed by surrounding tissue. For example, tumors of the pancreas and colon may absorb two to three times the volume of certain dyes, compared to normal cells. Once pre-sensitized by dye tagging in this manner, the cancerous or abnormal cells can be destroyed by irradiation with light of an appropriate wavelength or waveband corresponding to an absorbing wavelength or waveband of the dye, with minimal damage to surrounding normal tissue. Similarly, light activatable agents can be selectively administered to a specific treatment site, so that activation of such agents leads to tissue damage at the treatment site, but not surrounding tissue. Light activated drug therapy has been clinically used to treat metastatic breast cancer, bladder cancer, lung carcinomas, esophageal cancer, basal cell carcinoma, malignant melanoma, ocular tumors, head and neck cancers, and other types of malignant tissue growths. The light activated agent is either preferentially absorbed by the abnormal tissue, and/or is infused into vasculature that supplies the abnormal tissue, so that application of the light destroys the abnormal tissue. Because of the preferential drug absorption light activated drug therapy can kill malignant tissue with less effect on surrounding benign tissue than alternative treatment procedures.
Light is administered to an internal treatment site through an optical fiber from an external source such as a laser, or is applied to a site exposed during a surgical procedure, or is administered using an implantable probe. Several different embodiments of implantable light emitting probes for administering light activated therapy to an internal site within a patient's body are disclosed in commonly assigned U.S. Pat. No. 5,445,608. Further, a number of embodiments of flexible light emitting probes are disclosed in commonly assigned U.S. Pat. Nos. 5,800,478, 5,766,234, and 5,876,427. The above-referenced U.S. Pat. No. 5,445,608 teaches that an implantable probe containing a plurality of light sources can be transcutaneously introduced to a desired treatment site through a surgical incision and then left in place for an extended period of time so that the light emitted by light emitting diodes (LEDs) or other types of light sources mounted in the probe can administer light activated therapy to destroy abnormal tissue or other types of pathogenic organisms that have absorbed an appropriate photoreactive agent. Similarly, the flexible microcircuits disclosed in the above-noted patents are generally intended to be introduced into the body through a natural opening or through a small incision, and positioned at the treatment site using conventional endoscopic techniques. The flexibility of these microcircuits facilitates their insertion into the body and disposition at the treatment site. Additional light emitting probes are disclosed in commonly assigned U.S. Pat. No. 6,416,531, U.S. patent application Ser. No. 11/416,783, and U.S. patent application Ser. No. 12/445,061. It should be recognized that such implantable probes are exemplary, rather than limiting in regard to the concepts disclosed herein.
It has been recognized that synergistic effects can occur when different treatment methods are combined; however, successfully predicting such synergistic effects is rare.
It would be desirable to provide techniques for combining other treatment with light activated drug therapy treatment to achieve such a synergistic effect.